#app3 .square{
  border: 1px solid grey;
  margin-top: 7vw;
  margin-left: 10vw;
  width: 10vw;
  height: 10vw;
  transition: transform 1.5s;
}
#app3 .square.active{
  transform:translateX(15vw);
  border-radius: 50%
}